Chunks of Failed Planets Might Have Scarred Early Earth

Three views of the Apollo Basin taken with NASA’s Moon Mineralogy Mapper instrument on India’s Chandrayaan-1 spacecraft. The false-color image on the right reveals composition, which can help scientists discover the history of the moon’s surface and impact craters

The rocky worlds of the solar system may bear scars from the debris that didn’t quite make the cut as planets, a new research suggests.

Billions of years ago, when the solar system was very young, showers of material slammed into the infant Earth, its moon and Mars, in a period known as the Late Heavy Bombardment (LHB).

For years, studies have suggested that a group of rocks that now surround the modern-day asteroid belt between Mars and Jupiter were responsible for that early hammering of the inner solar system. Those rocks would have been thrown toward the sun as the gas-giant planets settled into their present-day orbits.

But new simulations suggest that the rocky debris between Mars and Jupiter may not deserve all of the blame. Instead, bits and pieces of the same material that formed the planets also might have peppered the young inner solar system bodies. [Solar System Evolution: Peering Back at the Sun’s Cosmic Womb]

“We have evidence for two early-bombardment populations and a time difference between them — a late one, plausibly made by escapees from the asteroid belt, and an early one from elsewhere,” William Bottke, an impact scientist at the Southwest Research Institute in Colorado, told Space.com.

Bottke presented his ongoing research on this subject at the 229th meeting of the American Astronomical Society in Grapevine, Texas, earlier this month. The research is based, in part, on new simulations he has run in the past few months. Over the past decade, as spacecraft have gathered more detailed looks at the moon and Mars, and models have become more sophisticated, Bottke found himself growing less convinced that the massive scarring on both worlds came from objects that originated in the asteroid belt.Source : Space